GUI/HUD Feature

[mattdesl]

I'm working in a feature/hud branch to test out the idea of a built-in GUI system for canvas-sketch. It would be like dat.gui but a bit more opinionated, a lot more declarative, and will integrate easily with canvas-sketch as well as features like exporting/importing serialized data (for example, making prints parameters reproducible).

Here is an example, no fancy styling yet:

And a video in this tweet.

It would be built with Preact to keep the canvas-sketch library small.

Syntax

I don't want to introduce a lot of new API concepts to users, and I want it to be declarative and in line with the rest of the ethos of pure render functions. My current thought is to have something like this:

• When params is passed to settings or update() function, the sketch will be added to a global HUD panel, and the panel will be made visible if it has one or more sketches attached to it.
• If the param is an object it can include settings like display name, min/max, etc.
• In the sketch & renderer functions, the param prop is converted into literal values (e.g. instead of a descriptor with options, you just get the raw number value).

const canvasSketch = require('canvas-sketch');

const settings = {
  dimensions: [ 640, 640 ],
  params: {
    background: 'pink',
    time: {
      value: 0.5,
      min: 0,
      max: 1,
      step: 0.001
    },
    number: 0.25,
    text: 'some text',
    download: ({ exportFrame }) => exportFrame()
  }
};

canvasSketch(() => {
  return ({ params }) => {
    const { background, radius } = params;
    console.log('Current background:', background); // e.g. #ff0000
    console.log('Current radius:', radius); // e.g. 0.523
  };
}, settings);

Motivation

It won't be all that different than dat.gui, but:

• It will work well out of the box, and will require zero "wiring" to get properties hooked up to GUIs or render events
• It will be declarative, so it can technically be stripped away by a higher-order function that passes props down (like React props & components)
• It will integrate well with canvas-sketch already, but can also make some nice considerations for exporting, e.g. serialize JSON to a file so that each frame/export is saved with the parameters, or adding a --params flag to the CLI tool to override params with a JSON file
• The global HUD can be a place for other requested features to canvas-sketch, like a play/pause, export button, etc

Features

Should support:

• Text input, number spinners, sliders, color input, 2D XY pad, 3D orbit rotation (?), drop-down, checkbox, buttons, file drag & drop (images etc), ...?
• Fuzzy searching of parameters to quickly drill down big lists?
• Folders or some other way of letting the user organize things?

Questions

• Syntax for buttons/click events? Often users will want to handle the event within the sketch function, rather than before the sketch loads. Maybe some sort of event system?
• Should the parameters be persisted with localStorage? etc.
• How to serialize/unserialize the parameters?
• How to map params to built-in sketch properties like time, dimensions, duration etc?
• Is this a can of worms I don't even want to get into?